In a recent challenge issued by NASA, university students were asked to design an electric aircraft envisaged to enter service in the year 2020 and be commercially competitive with standard piston-engine craft. In response, the space agency received submissions from 20 universities across the United States that not only met the brief but, in many cases, went above and beyond to really the impress the judges. We take a look at the top five prize winners.

The designs were assessed not only on their merit, but also considered in regard to the student university level. As such, submissions were categorized into graduate and undergraduate design studies and judged accordingly.

Graduate Level

Vapor

The one-and-only winner of this section was Tom Neuman, a graduate student with a Master’s of aerospace engineering at the Aerospace Systems Design Laboratory at the Georgia Institute of Technology. His design brought in twin 8 ft (2.5 m) tail-mounted propellers that, according to Neuman, were computer-modeled to achieve 92 percent efficiency.

With an efficient laminar flow fuselage design and retractable landing gear to further reduce drag, Vapor has a claimed 25 percent reduction in parasitic drag when compared to a Cirrus SR22 aircraft used as a standard light-aviation benchmark.

Designed to be powered by a proton exchange membrane fuel-cell (PEMFC), Neuman claims to have modeled a specific-energy of 800 Wh/kg in his design study at an impressive 55 percent efficiency. With this set-up, Vapor is expected to be capable of 800 nautical miles (1,482 km) at a cruising speed of around 150 knots (278 km/h).

Undergraduate Level

Bladessa

In first place in this category is a design produced by a team of students from the University of California, Davis (UC Davis). The design is more conventional with twin wing-mounted motors. A puller-propeller concept intended to be built using composite materials, the electric power-plants are intended to be driven by a bank of rechargeable Lithium-ion batteries.

Ethan Kellogg and team members produced a performance design claim of 135 knot (250 km/h) cruising speed and a range of 520 nautical miles (963 km) for Bladessa. With 270 horsepower (200 Kw) on tap, the Bladessa design is intended to have a maximum take-off weight of around 4,200 lb (1,900 kg), including up to 700 lb (317 kg) of payload.

Again, laminar flows have been carefully modeled to achieve maximum efficiency and minimum drag on and around the fuselage of the aircraft.

Areion

In second place was another UC Davis design, this time a pusher-propeller type with a forward canard. Presumably named after the winged immortal horse born to the goddess Demeter, this contender's configuration is also designed to decrease the area and drag of the main wing by using a blended airfoil design and a set of imaginatively-named hyperelastic flaperons.

According to the team led by fourth year undergraduate, Louis Edelman, this enables the usage of Natural Laminar Flow (NLF) technology to reduce energy requirements over the flight envelope.

Again an all-electric aircraft, power and flight characteristic details are sparse, but the team does say that it would be a hydrogen-powered fuel-cell that provided the energy.

BeamTree PH-10

Bringing up third place in the list of winners was a design from a team at Virginia Tech. With a 48.5 ft (14.7 m) wingspan, an AC induction motor, and three lithium-ion battery packs, the BeamTree PH-10 is designed to be capable of a cruise speed of 175 knots (325 km/h) for an impressive distance of 783 nautical miles (1,450 km).

The large mass of the electric propulsion system was the main design driver for the Virginia Tech team who envisaged a tadpole fuselage to reduce profile drag along with winglets to help better aerodynamic efficiency.

SCUBA Stingray

Rounding out the top five is the SCUBA Stingray design – yet another
entrant from UC Davis – which received an honorable mention. Designed to
use a cutting-edge hybrid
aluminum-air/lithium ion battery system for
long range and heavy payload capacity.

Design specifications include a four-passenger
carrying capacity, along with a claimed range of at least 500
nautical miles (926 km), carrying a payload in excess of 400 lb (180
kg), all while cruising at a speed greater than 130 knots (240 km/h).

The outstanding design aspects of the Stingray, according to the team, are tapered primary and horizontal wings, fixed tricycle landing gear, along with a substantial T-tail empennage.

According to NASA, the ideas of these students are more than mere academic
exercises; research at the space agency in aeronautics also includes finding ways to cut back on fossil fuel dependence and reduce the aviation sector's pollution emissions, including lessening noise
around airports.

"The research and critical thinking that went into each of these
designs was very impressive," said Jaiwon Shin, NASA's associate administrator for aeronautics. "It's clear there is a new generation of
aeronautical innovators nearly ready to make their mark on the future of
aviation."

Winners of this challenge will be invited to visit NASA in October to present their work.